HI Gregory, On 10/17/24 at 03:03pm, Gregory Price wrote: > walk_system_ram_res_rev() erroneously discards resource flags when > passing the information to the callback. > > This causes systems with IORESOURCE_SYSRAM_DRIVER_MANAGED memory to > have these resources selected during kexec to store kexec buffers > if that memory happens to be at placed above normal system ram. Sorry about that. I haven't checked IORESOURCE_SYSRAM_DRIVER_MANAGED memory carefully, wondering if res could be set as 'IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY' plus IORESOURCE_SYSRAM_DRIVER_MANAGED in iomem_resource tree. Anyway, the change in this patch is certainly better. Thanks. Acked-by: Baoquan He <bhe@xxxxxxxxxx> > > This leads to undefined behavior after reboot. If the kexec buffer > is never touched, nothing happens. If the kexec buffer is touched, > it could lead to a crash (like below) or undefined behavior. > > Tested on a system with CXL memory expanders with driver managed > memory, TPM enabled, and CONFIG_IMA_KEXEC=y. Adding printk's > showed the flags were being discarded and as a result the check > for IORESOURCE_SYSRAM_DRIVER_MANAGED passes. > > find_next_iomem_res: name(System RAM (kmem)) > start(10000000000) > end(1034fffffff) > flags(83000200) > > locate_mem_hole_top_down: start(10000000000) end(1034fffffff) flags(0) > > [.] BUG: unable to handle page fault for address: ffff89834ffff000 > [.] #PF: supervisor read access in kernel mode > [.] #PF: error_code(0x0000) - not-present page > [.] PGD c04c8bf067 P4D c04c8bf067 PUD c04c8be067 PMD 0 > [.] Oops: 0000 [#1] SMP > [.] RIP: 0010:ima_restore_measurement_list+0x95/0x4b0 > [.] RSP: 0018:ffffc900000d3a80 EFLAGS: 00010286 > [.] RAX: 0000000000001000 RBX: 0000000000000000 RCX: ffff89834ffff000 > [.] RDX: 0000000000000018 RSI: ffff89834ffff000 RDI: ffff89834ffff018 > [.] RBP: ffffc900000d3ba0 R08: 0000000000000020 R09: ffff888132b8a900 > [.] R10: 4000000000000000 R11: 000000003a616d69 R12: 0000000000000000 > [.] R13: ffffffff8404ac28 R14: 0000000000000000 R15: ffff89834ffff000 > [.] FS: 0000000000000000(0000) GS:ffff893d44640000(0000) knlGS:0000000000000000 > [.] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [.] ata5: SATA link down (SStatus 0 SControl 300) > [.] CR2: ffff89834ffff000 CR3: 000001034d00f001 CR4: 0000000000770ef0 > [.] PKRU: 55555554 > [.] Call Trace: > [.] <TASK> > [.] ? __die+0x78/0xc0 > [.] ? page_fault_oops+0x2a8/0x3a0 > [.] ? exc_page_fault+0x84/0x130 > [.] ? asm_exc_page_fault+0x22/0x30 > [.] ? ima_restore_measurement_list+0x95/0x4b0 > [.] ? template_desc_init_fields+0x317/0x410 > [.] ? crypto_alloc_tfm_node+0x9c/0xc0 > [.] ? init_ima_lsm+0x30/0x30 > [.] ima_load_kexec_buffer+0x72/0xa0 > [.] ima_init+0x44/0xa0 > [.] __initstub__kmod_ima__373_1201_init_ima7+0x1e/0xb0 > [.] ? init_ima_lsm+0x30/0x30 > [.] do_one_initcall+0xad/0x200 > [.] ? idr_alloc_cyclic+0xaa/0x110 > [.] ? new_slab+0x12c/0x420 > [.] ? new_slab+0x12c/0x420 > [.] ? number+0x12a/0x430 > [.] ? sysvec_apic_timer_interrupt+0xa/0x80 > [.] ? asm_sysvec_apic_timer_interrupt+0x16/0x20 > [.] ? parse_args+0xd4/0x380 > [.] ? parse_args+0x14b/0x380 > [.] kernel_init_freeable+0x1c1/0x2b0 > [.] ? rest_init+0xb0/0xb0 > [.] kernel_init+0x16/0x1a0 > [.] ret_from_fork+0x2f/0x40 > [.] ? rest_init+0xb0/0xb0 > [.] ret_from_fork_asm+0x11/0x20 > [.] </TASK> > > Link: https://lore.kernel.org/all/20231114091658.228030-1-bhe@xxxxxxxxxx/ > Fixes: 7acf164b259d ("resource: add walk_system_ram_res_rev()") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Gregory Price <gourry@xxxxxxxxxx> > --- > kernel/resource.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/kernel/resource.c b/kernel/resource.c > index b730bd28b422..4101016e8b20 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -459,9 +459,7 @@ int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > rams_size += 16; > } > > - rams[i].start = res.start; > - rams[i++].end = res.end; > - > + rams[i++] = res; > start = res.end + 1; > } > > -- > 2.43.0 >
